Phase change interface stability during isochoric solidification of an aqueous solution

Authors: ZHAO, YUANHENG - University Of California Berkeley; POWELL-PALM, MATTHEW - University Of California Berkeley; UKPAI, GIDEON - University Of California Berkeley; Bilbao-Sainz, Cristina; LIUBIAO, CHEN - University Of Chinese Academy Of Sciences; WANG, JUNJIE - University Of Chinese Academy Of Sciences; RUBINSKY, BORIS - University Of California Berkeley

Submitted to: Applied Physics Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2020
Publication Date: 9/28/2020
Citation: Zhao, Y., Powell-Palm, M., Ukpai, G., Bilbao-Sainz, C., Liubiao, C., Wang, J., Rubinsky, B. 2020. Phase change interface stability during isochoric solidification of an aqueous solution. Applied Physics Letters. 117(13). Article 133701. https://doi.org/10.1063/5.0019878.
DOI: https://doi.org/10.1063/5.0019878

Interpretive Summary: The solidification process in aqueous solutions is of fundamental interest in understanding the physics of ice. One important aspect of the aqueous solution solidification process is the microstructure of the ice crystals that form upon freezing. The dendritic ice structures that form during conventional freezing of biological matter yield major deleterious effects in the quality of frozen foods. The primary factors dictating the development of dendritic instabilities are the interfacial temperature and the mass concentration of solutes in the advancing solid liquid interface. We have developed a mathematical model of heat and mass transfer during solidification of aqueous solutions under isochoric and isobaric conditions and predict the stability of the solid liquid interface during solidification of a physiological saline solution (0.9% w/v NaCl). We found that isochoric thermodynamic conditions significantly enhance the stability of the interface, delaying the transition from a stable planar configuration until very late in the solidification process, which suggest the potential for reduction of the additional mechanical damage associated with dendritic ice formation during cryopreservation of biological matter.

Technical Abstract: The stability of solid–liquid interfaces during solidification is a physical phenomenon of fundamental interest with a wide range of practical applications, including the freezing of biological matter for medical and agricultural purposes. Much of the classical research in this field treats solidification in isobaric (constant-pressure) systems in which the phase transition typically occurs under constant atmospheric pressure. Recent research has found, however, that freezing in isochoric (constant-volume) systems in which the solidifying material is confined within a high-strength constant-volume chamber held at subfreezing temperatures gives rise to many atypical physical phenomena, and understanding of the solid–liquid interface behavior under isochoric conditions is currently lacking. In this work, we study the stability and propagation of the solid–liquid interface during isochoric freezing of aqueous solutions. Using a mathematical model of heat and mass transfer during solidification coupled with multiple criteria for predicting the emergence of interfacial instabilities based on temperature and concentration gradients in the phase transition region, we find that isochoric freezing significantly stabilizes the solid–liquid interface relative to isobaric freezing, suggesting the potential for extended growth of planar, non-dendritic interfaces.